لخّصلي

G antigen was first described as a part of Rhesus (Rh) blood group system and is dependent on the expression of both the RHCECe and RHD alleles [1].In fact, the accurate differentiation of anti-D, anti-C, and anti-G is essential to decide whether Rh(D) prophylaxis should be given or not in alloimmunized pregnancies [7,8], to diagnose the accurate type of HDFN and to avoid the occurrence of potential Rh alloimmunization or transfusion reaction in D negative patients.The basis of reactivity for G antigen is Ser103, which is encoded by RHD and by the C allele of RHCE genes [5].Anti-D is the most common antibody responsible for severe hemolytic disease of the fetus and newborn (HDFN), but other Rh antibodies, such as anti-C, anti-E, anti-e, and anti-G, can also cause HDFN [2,5].Most individuals who do not carry an RHD or RHCECe allele would be expected to be negative for G antigen [[2], [3], [4]], but there are some exceptions, such as lack of G antigen in a very small number of D + C- people or the presence of G antigen in a very small number of D-C- people [3].

G antigen was first described as a part of Rhesus (Rh) blood group system and is
dependent on the expression of both the RHCECe and RHD alleles [1]. Most
individuals who do not carry an RHD or RHCECe allele would be expected to be
negative for G antigen [[2], [3], [4]], but there are some exceptions, such as lack of G
antigen in a very small number of D + C- people or the presence of G antigen in a very
small number of D-C- people [3]. The basis of reactivity for G antigen is Ser103, which
is encoded by RHD and by the C allele of RHCE genes [5]. Hence, the apparent co
distribution of G antigen with either C or D antigen causes anti-G to appear serologically
as anti-C plus anti-D [1,3]. There are actual five possibilities for the patterns of anti-G or
anti-D plus anti-C: anti-G + anti-D + anti-C, anti-G + anti-D, anti-G + anti-C, anti-D + anti
C, or anti-G alone [3,6]. In 27 alloimmunized women initially identified as containing
anti-D + anti-C, the combination of anti-G + anti-C, anti-D + anti-G, anti-D + anti-C, and
anti-D + anti-C + anti-G occurred in 14.8%, 25.9%, 11.1%, and 48.1%, respectively, and
anti-G was presented in combination with anti-D and/or anti-C in 24 samples (88.9%)
[6]. Hence, anti-G may not be so rare, and perhaps it is often under-diagnosed in the
routine laboratory.
Anti-D is the most common antibody responsible for severe hemolytic disease of the
fetus and newborn (HDFN), but other Rh antibodies, such as anti-C, anti-E, anti-e, and
anti-G, can also cause HDFN [2,5]. Meanwhile, some medical or social complications
can be encountered and reasonably explained by the presentation of anti-G rather than
anti-D. For instance, HDFN due to anti-D was diagnosed even though the parents were
D negative, or anti-D was induced in D negative patients after the transfusion of D
negative blood [2,7]. In fact, the accurate differentiation of anti-D, anti-C, and anti-G is
essential to decide whether Rh(D) prophylaxis should be given or not in alloimmunized
pregnancies [7,8], to diagnose the accurate type of HDFN and to avoid the occurrence
of potential Rh alloimmunization or transfusion reaction in D negative patients. In this
report, we described a rare case of anti-G together with anti-D and anti-C in a pregnant
woman as well as her female neonate who had experienced mild HDFN and only
received phototherapy during hospitalization.